diff --git a/POLHE3_SCRIPTS/Calibration_files-Junhao_DC/scripts/DC_calib.C b/POLHE3_SCRIPTS/Calibration_files-Junhao_DC/scripts/DC_calib.C
index 3af1caf233197c18b1e2ac3129309ed144d9413e..5583db223d8725f8fb4e03c6c25c2111613130c1 100644
--- a/POLHE3_SCRIPTS/Calibration_files-Junhao_DC/scripts/DC_calib.C
+++ b/POLHE3_SCRIPTS/Calibration_files-Junhao_DC/scripts/DC_calib.C
@@ -1392,7 +1392,7 @@ void DC_calib::FitWireIntegralDriftTime(string fitFunc)
 
 
 	TF1 *tZero_fit = new TF1("tZero_fit", "[0]*x + [1]", MINBIN, MAXBIN);
-	TF1 *tZero_fit_heaviside = new TF1("tZero_fit_heaviside", "([1]*(x-[0])+[2]*(x-[0])^2+[3]*(x-[0])^3+[4])/(1+e^(-1000*(x-[0]))+[4]/(1+e^(-1000*([0]-x)))", MINBIN, MAXBIN);
+	TF1 *tZero_fit_heaviside = new TF1("tZero_fit_heaviside", "([1]*(x-[0])+[2]*(x-[0])^2+[3]*(x-[0])^3+[4])/(1+e^(-1000*(x-[0])))+[4]/(1+e^(-1000*([0]-x)))", MINBIN, MAXBIN);
 
 	//Loop over Planes
 	for (Int_t ip = 0; ip < NPLANES; ip++){